Summary
Synaptic actions evoked from primary afferents and the sensorimotor cortex in neurones of the dorsal spinocerebellar tract were investigated: 1. Stimulation of the anterior lobe of the cerebellum produced a small IPSP in only one but not in the other six neurones examined. 2. IPSPs were induced not only from group I fibres (in 41% of group I neurones) but also from cutaneous and/or high threshold muscle afferents (in 37%). 3. Stimulation of the contralateral sensorimotor cortex evoked IPSPs in 80% of group I neurones. The IPSP had a latency of 10–15 msec and lasted for 40–100 msec. EPSPs were evoked from the cortex in a small number of neurones. 4. Effects from the cortex were compared with those from primary afferents in individual neurones. The cortical IPSPs were induced independently of whether the neurone received monosynaptic EPSP from extensor or flexor group I fibres. The cortical IPSPs (or EPSPs) occurred more frequently in neurones which exhibited polysynaptic IPSPs (or EPSPs) from primary afferents. 5. The few FRA neurones encountered were all excited from the cortex.
Excitability measurements of primary afferent terminals in or near Clarke's column showed that a terminal depolarization is evoked from the cortex in group Ib but not in Ia afferents.
The relative importance of post-and presynaptic inhibition of transmission to the DSCT is discussed.
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Hongo, T., Okada, Y. Cortically evoked pre-and postsynaptic inhibition of impulse transmission to the dorsal spinocerebellar tract. Exp Brain Res 3, 163–177 (1967). https://doi.org/10.1007/BF00233260
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DOI: https://doi.org/10.1007/BF00233260